In Russian, at least, the country remains “Germany” but the people from it are the “mute-sies”, unlike pretty much every other pairing of country name / demonym.
In Italy Germany is Germania, but Germans are tedeschi and German (the language) is also tedesco. (BTW, we lowercase people and languages and weekdays and months, but this is changing - English leads.)
The reason seems to be the Latin word theodiscus from Old German theod / people.
Interesting tangent, but I believe this is also a slavic surname and is anglicised as Nimitz. And before you know it you have an aircraft carrier called USS Mute.
Apparently it's most likely tied to the German municipality of Waake or the Swedish tribe of Vagoths. However most Lithuanians would likely explain it in the form of a joke - either about Germans being thieves ('vogti' = to steal) in reference to Teutonic/Livonic ordins, or about them being 'tough' or well armored ('vo kiets' ~= 'wow, tough/hard').
Another fun fact: at least in Croatia, we colloquially call them "schwabs" which originates from another group of germanic people https://en.wikipedia.org/wiki/Suebi
It comes from the fact that Germany didn't unify until very late, so the people were called by the small city-states that they came from. In American revolutionary war, some British mercenaries were called Hessians....
According to Wikipedia [1], it’s a matter of some debate, with the theories being the (standard) corruption of a name for the first Western Baltic people encountered, or a take on the “unintelligible war cry” people from the Latvian root for speaking.
Similarly, the word "barbarian" comes from the ancient Greeks describing the people who lived around them as sounding like they were saying "bar bar bar".
The word is probably borrowed into Hungarian from Slavic. We have a similar word in our language as well, but it's used as someone who doesn't understand. Also used interchangeably with Turk.
No, it's very similar to nemec, basically the same thing also borrowed from Slavic. The "c" ending is pronounced as "ts". The full phrase goes like: "Why don't you understand, are you German/Turk?" (as in not understanding the language). There's also a place, a citadel and river with that name, which your ancestors might have been familiar with:
Mute, because he can't speak our language.